Continued advances in the field of consumer electronics and appliances have added a significant number of features to these devices which make their operation simpler, while at the same time increasing their overall functionality. Most pieces of consumer electronics and appliances manufactured today include some sort of computer control within the unit itself. These computers control everything from automatically remembering leap year and adjusting the number of days in February, to the on-screen menu display, picture in picture control, cook cycle time control, to name just a few. While these microprocessors are controlling ever increasing functionality of the consumer electronic devices and appliances into which they are incorporated, their capacity for further increases remains vast. Even with these advanced features and computer control, modern manufacturing techniques have allowed the cost of these devices to decrease since their initial introduction onto the market. However, even with such decreases, the cost of these electronic devices and appliances still remains fairly expensive.
A persistent problem with electronic appliances exists mainly due to their expense and ease of portability. This problem is the ease with which electronic appliances are stolen from homes, warehouses, and during transit. Because these devices are so enjoyable to own, and yet are priced out of the reach of many citizens, a significant market for stolen electronic appliances exists. Their ease of portability and lack of security features and identification, as well as the relativity high probability that the recipient of the stolen merchandise will not be caught, or if so not prosecuted, only exacerbates this problem. Currently, most consumer electronics devices only carry a written serial number on the device to identify it in the event of a theft, however, since many individuals fail to record or register this serial number, attempts to recover merchandise once it has been stolen often prove futile.
At the manufacturing level, companies are continually looking for new methods to keep track of their inventory in an effort to better manage the business and prevent loss through theft. One relatively new technology which many companies are now beginning to utilize is a system of product identification and tracking known as RFID (radio frequency identification). This new technology is primarily used for inventory control and tracking within the factory area and warehouse, and is typically associated with the packaging of the product (a RFID label or tag on the box), and not with the product itself.
RFID systems use radio frequency to identify, locate, and track items through a system comprising primarily of three components. The system operates under control of a host computer which contains all of the inventory database information required for operation of this system. A passive RFID tag is the second component of the system and is typically applied via a disposable label to product packaging in similar fashion to a bar code tracking label. This disposable label contains an antenna coil and a silicon chip, and requires no separate power source. The silicon chip includes basic modulation circuitry and non-volatile memory to store product identification information. This disposable label is energized by the third component of the system, a RFID reader or interrogator, which transmits a RF signal to the disposable label. As the radio frequency signal passes through the antenna coil, an AC voltage is generated thereacross. This voltage is rectified to supply power to the silicon chip which then transmits the information stored therein back to the reader. This information transmission technique is commonly known as backscattering.
Current RFID labels work in one of three frequency ranges. Low frequency tags generally operate below 135 kHz and are commonly used for access control and industrial control. While energy at this frequency readily moves through people and other obstacles, data rates are relatively low compared to those of other technologies. Another frequency band used for RFID labels centers around 2.45 GHz, and operates under the same regulatory guidelines as local area networks OpenAir and 802.11. While data rates are greatly increased over the low frequency systems, the ability to transmit this energy through obstacles is somewhat reduced. A benefit of this higher frequency system is that the antennas may be much smaller, and can be etched or screen printed instead of wound from wire. The third frequency band commonly used for RFID labels is 13.56 MHz, a frequency that has been allocated in much of the industrialized world. While data rates are higher and antennas are smaller than with other frequencies, the read ranges are often shorter. A benefit of using this frequency exists due to the world wide allocation of this frequency which means that products may be deployed around the world with little or no modification to the RHD label.
The amount of information which is able to be carried by a RFID label is be quite large. One commercial implementation of a RFID label is marketed by Texas Instruments under the name Tag-It. These commercially available RFID labels provide 256 bytes of user programmable read/write memory partitioned into eight 32 byte blocks. A ninth block contains revision and manufacturing information, while a tenth block contains a unique 32 byte ID code sequentially assigned during manufacturing which is able to provide 4.3 billion unique label identities. Other designs including more or fewer programmable bytes are also available. The distance at which the readers may read the memory information from the RFID label depends on environmental conditions and obstructions, and for the TI Tag-It label is roughly equivalent to distances achievable by state of the art hand held CCD bar code scanners. However, whereas bar codes must be visible and relatively close to the reader in order to be read, the RFID label may be hidden from view, and depending on the design, may be read from several feet away, perhaps even 100 yards away without human intervention.
In addition to increasing the distances at which RFID labels may be utilized, the technology associated with RFID continues to increase the number of RFID labels which may be read simultaneously by a single reader. Various systems exist for simultaneous RFID tag communication. One such method marketed by Texas Instruments is known as SID (Simultaneous Identification) and is currently able to read thirty tags per second. The SID algorithm uses a binary tree search through the unique code stored in the RFID label, using commands that can silence tags momentarily to allow the read of information from other tags. Another system takes advantage of a pseudo random number generator within the RFID label to command the tags to stop transmitting until a generated pseudo random number counts down. In this way, the probability of two tags counting down to the same pseudo random number and beginning to retransmit simultaneously is sufficiently low to allow proper operation of the system.
While the RFID label system promises great advances in the field of product tracking and inventory control, its ability to prevent theft is somewhat limited. Specifically, since the RFID labels are placed on product packaging, a thief would merely need to remove this label from the packaging in order to defeat any further tracking of the product. Alternatively, a thief would simply need to remove the product from the packaging to also defeat further product tracking. A product so stolen remains fully operational, and therefore, has a high black market value.
While the removal of the RFID label from the product packaging could be overcome by installing this label within the product itself, limitations on the distance at which a product may be scanned, the time required to complete the scan, and the reduced ability to scan information through obstacles greatly reduces the ability of these RFID) labels to provide theft deterrence. Specifically, products could be removed from a warehouse by placing an appropriate shield between the product and the readers to prevent detection of the theft at the first instance. However, even if the readers were able to detect the actual theft of the products, since these products remain fully operational and since the ability to detect the RFID label over distance and through obstacles in very difficult at the power levels of conventional RFID labels, the probability of recovering the stolen merchandise is very small once sold on the black market. Theft during transit of these products is even less problematic for the thief since there are no readers to defeat which would provide initial detection of the theft. 1995 estimates of theft within the freight industry alone is $10 billion dollars. This equates to 2.5% of $400 billion dollar industry.
One of the reasons for such a high volume of theft, as mentioned briefly above, is because the electronic devices are so enjoyable to own. The continued advances with the consumer electronics have greatly simplified their use both in terms of programmability and user interaction. One user interaction feature with which most consumers have become quite accustomed is the ability to remotely control their TV, stereo, VCR, camcorder, etc. While several items of consumer electronics offer this remote control feature in a line-of-sight fashion with a hand held remote controller, the desire to electrically remotely control other appliances in a non-line-of-sight fashion also exists.
In order to fulfill this desire to allow remote control of home appliances, electronic equipment, lighting, etc. several systems have been developed which allow control communications over a home's, electrical wiring system. However, since most home appliances and electronic equipment do not include communications and control circuitry to allow reception of the electrical system communication control signals, many of the systems which have been developed utilize separate plug-in modules which interface between an appliance's electrical cord and the home electrical outlet. While there is currently still no universally accepted standard for this communication over a home's electrical wiring system, two protocols have emerged as the forerunners, and serve as a basis for many of the systems currently designed. The first such protocol is commercially known and marketed as the X-10 communications protocol. The second communications protocol which appears to be in wide use at this time is known as the consumer electronics bus protocol (CEBus). However, as mentioned above, neither one of these two has gained universal acceptance in the design of remotely controllable systems for home consumer appliances, lighting, etc. Indeed, several systems which claim to allow remote control of home appliances, lighting, etc., utilize their own communications protocol which does not adhere to either one of the two aforementioned communication protocol forerunners.
Exemplary systems which claim to allow remote control of home appliances, lighting, etc., may be found with reference to the following documents: U.S. Pat. Nos. 4,567,557; 5,051,720; 5,334,975; 5,400,246; 5,471,190; 5,491,463; 5,554,968; 5,570,085; 5,621,662; and European Patent Application No. 89 121025.4 bearing Publication No. 0 369 382 A2. The disclosure of each of these documents, particularly as they relate to communications protocols allowing remote communications over an electrical distribution system, are hereby incorporated by reference.
While each of the above-identified systems claim certain benefits for a remotely controllable system, none of the systems are able to distinguish individual appliances within a household, other than by their physical or programmed location within the household. Specifically, many of the above systems utilize separate control modules which are plugged into the house's electrical outlets, and may be themselves remotely controlled via communication received over the electrical wiring system. However, if one were to unplug a particular appliance from one of these modules and move it to a different physical location within the house, the remote control system has no way of knowing that this has taken place without manual user interaction. While this reprogramming may seem to be a minor problem in view of the infrequency with which most consumer electronics and appliances are actually moved within a household, in view of the fact that many people have trouble reprogramming their VCR clock, it is a problem to be avoided nonetheless.
The unacceptability of this problem may be best highlighted through an example. Assuming without admitting, that a remotely controlled system were capable of disabling a device, such as a television, at a certain time, if a parent were to disable a television set located in a child's room after 8:00 PM, a child would only have to unplug the television set from the current electrical receptacle and replug the television set into a different electrical receptacle in order to defeat the system programming and allow continued television viewing after 8:00 PM. While the parent could conceivably disable all of the electrical outlets to the child's room, such is undesirable as this would prevent the child from using a night light, clock radio alarm, etc. in his room. While this may appear to be a simplistic example, parents with kids who own video games may well disagree.
Another problem which exists from the user stand point, as discussed above from the manufacturer and transportation stand point is the ease at which these electronic devices are stolen from the home. In addition to the significant financial loss which must be borne by the homeowner as a result of a theft of these electronic devices, a significant safety risk exists to the homeowner from the presence of the thief within the home. While the presence of electronic devices may not be sole cause for home break-ins and thefts, the ease with which these items may be transported and sold on the black market certainly provides an incentive for these thieves.
A device which attempts to overcome this problem is described in U.S. Pat. No. 5,021,779, issued to Bisak on Jun. 4, 1991 for a SECURITY DFVICE. The system contemplated by this patent utilizes a receiver-dccoder which is adapted and arranged to allow the appliance to operate in its normal mode when the receiver-decoder receives a predetermined code carried via the electrical wiring system within the home. If this predetermined code is not received by the receiver-decoder, the appliance enters a security mode of operation. Various alternative security modes of operation are described in this patent including the use of an alarm within the device, to trigger a transmitter device to sound an external alarm, or to transmit a silent signal to the police department upon being plugged in to allow the apprehension of the thieves. The encoder-transmitter of this system is arranged to frequency or phase modulate a carrier signal with a binary digital code and transmit that signal over the electrical wiring system to the electronic appliance plugged into the wall socket of the household. Once a consumer has set a particular code and transmitted that code over the electrical system to the electronic appliance, that code is kept in memory and used to compare subsequent receptions to determine of the appliance is still connected within that consumer's household.
However, as with the above-described control systems, the system of the Bisak '779 patent does not allow for individual identification of electronic appliances coupled to the system. Nor does this system allow any type of control of the electronic devices coupled to the electrical system of house. Further, this security device operates on its own communications protocol operating at 260 kHz and transmitting a unique binary digital code which is suited only to the security feature. The system of Bisak '779 also does not address the problem of theft at the manufactory or transportation levels.